Parenteral medium-chain triglyceride-induced neutrophil activation is not mediated by a Pertussis Toxin sensitive receptor

BACKGROUND & AIMS

Lipid-induced immune modulation might contribute to the increased infection rate that is observed in patients using parenteral nutrition. We previously showed that emulsions containing medium-chain triglycerides (LCT/MCTs or pure MCTs), but not pure long-chain triglycerides (LCTs), impair neutrophil functions, modulate cell-signaling and induce neutrophil activation in vitro. It has recently been shown that medium-chain fatty acids are ligands for GPR84, a pertussis toxin (PT)-sensitive G-protein-coupled receptor (GPCR). This finding urged us to investigate whether MCT-induced neutrophil activation is mediated by PT-sensitive GPCRs.

METHODS

Neutrophils isolated from blood of healthy volunteers were pre-incubated with PT (0.5-1 microg/mL, 1.5 h) and analyzed for the effect of this pre-incubation on LCT/MCT (2.5 mmol/L)-dependent modulation of serum-treated zymosan (STZ)-induced intracellular Ca(2+) mobilization and on LCT/MCT (5 mmol/L)-induced expression of cell surface adhesion (CD11b) and degranulation (CD66b) markers and oxygen radical (ROS) production.

RESULTS

PT did not inhibit the effects of LCT/MCT on the STZ-induced increase in cytosolic free Ca(2+) concentration. LCT/MCT increased ROS production to 146% of unstimulated cells. However, pre-incubation with PT did not inhibit the LCT/MCT-induced ROS production. Furthermore, the LCT/MCT-induced increase in CD11b and CD66b expression (196% and 235% of unstimulated cells, respectively) was not inhibited by pre-incubation with PT.

CONCLUSION

LCT/MCT-induced neutrophil activation does not involve the action of a PT-sensitive G-protein-coupled receptor.

Microsomal epoxide hydrolase genotypes and the risk for head and neck cancer

BACKGROUND

Microsomal epoxide hydrolase (mEH) is an enzyme involved in the metabolism of (pre)carcinogens in tobacco smoke. We investigated whether functional genetic polymorphisms in mEH may have a risk-modifying effect on head and neck carcinogenesis.

METHODS

Blood from 429 patients with oral, pharyngeal, and laryngeal carcinoma and 419 healthy subjects was investigated for mEH polymorphisms.

RESULTS

Logistic regression analysis did not show differences in mEH genotype distributions between patients and controls, when categorized according to predicted mEH enzyme activity. Also no differences were found when evaluated according to tumor localization, sex, or tobacco consumption. A significantly higher incidence of the 139Arg/Arg variant was found in patients with hypopharyngeal carcinoma compared with controls (OR = 4.39, 95% CI = 1.45 to 13.35).

CONCLUSION

In contrast to earlier reports, we could not demonstrate a risk-modifying effect of genetic polymorphisms in mEH on head and neck carcinogenesis, except for the predicted high activity variant in patients with hypopharyngeal carcinoma.

Detoxification enzyme polymorphisms are not involved in duodenal adenomatosis in familial adenomatous polyposis

Background

Patients with familial adenomatous polyposis (FAP) are at high risk of developing duodenal adenomas and carcinomas. Besides germline mutations in the adenomatous polyposis coli (APC) gene, additional factors may influence the age of onset and number of duodenal adenomas. This study compared the genotype distributions of duodenal detoxification enzyme isoforms in patients with FAP and controls.

Methods

The study included 85 patients with FAP and 218 healthy age- and sex-matched controls. Genotyping of all participants using polymerase chain reaction was performed to detect polymorphisms in isoforms of uridine 5′-diphosphate glucuronosyltransferases (UGTs) and glutathione S-transferases (GSTs): UGT1A1, UGT1A3, UGT1A4, UGT1A6, UGT1A10, UGT2B4, UGT2B7, UGT2B15, GSTA1, GSTP1, GSTM1 and GSTT1.

Results

The variant genotypes of UGT1A3 were less common in patients with FAP than in controls (odds ratio 0·39 (95 per cent confidence interval 0·22 to 0·67)). There were no associations between FAP and the other polymorphic genes. The polymorphisms investigated had no predictive value for the severity of duodenal adenomatosis in patients with FAP.

Conclusion

Although the variant genotypes of UGT1A3 were less common in patients with FAP than in those without, this did not modulate the severity of duodenal adenomatosis.

Liver manipulation causes hepatocyte injury and precedes systemic inflammation in patients undergoing liver resection

Background

Liver failure following liver surgery is caused by an insufficient functioning remnant cell mass. This can be due to insufficient liver volume and can be aggravated by additional cell death during or after surgery. The aim of this study was to elucidate the causes of hepatocellular injury in patients undergoing liver resection.

Methods

Markers of hepatocyte injury (AST, GSTα, and L-FABP) and inflammation (IL-6) were measured in plasma of patients undergoing liver resection with and without intermittent inflow occlusion. To study the separate involvement of the intestines and the liver in systemic L-FABP release, arteriovenous concentration differences for L-FABP were measured.

Results

During liver manipulation, liver injury markers increased significantly. Arterial plasma levels and transhepatic and transintestinal concentration gradients of L-FABP indicated that this increase was exclusively due to hepatic and not due to intestinal release. Intermittent hepatic inflow occlusion, anesthesia, and liver transection did not further enhance arterial L-FABP and GSTα levels. Hepatocyte injury was followed by an inflammatory response.

Conclusions

This study shows that liver manipulation is a leading cause of hepatocyte injury during liver surgery. A potential causal relation between liver manipulation and systemic inflammation remains to be established; but since the inflammatory response is apparently initiated early during major abdominal surgery, interventions aimed at reducing postoperative inflammation and related complications should be started early during surgery or beforehand.

Susceptibility to pre-eclampsia is associated with multiple genetic polymorphisms in maternal biotransformation enzymes

BACKGROUND/AIMS

Probably no single gene is responsible for pre-eclampsia, but the disease merely is the result of polymorphisms in several genes in association with environmental factors. We therefore studied the simultaneous occurrence of several genetic polymorphisms in biotransformation enzymes in women who had developed pre- eclampsia, either with or without the HELLP syndrome, in comparison with healthy controls.

METHODS

The results of two previous studies on genetic polymorphisms in glutathione S-transferases P1, M1 and T1, epoxide hydrolase (EPHX) and cytochrome P4501A1 (CYP1A1) in 167 women with a history of pre-eclampsia and in 110 controls were combined. chi(2) analyses were used for statistical evaluation of the number of polymorphisms between cases and controls.

RESULTS

There was a significant association with the number of genetic polymorphisms in biotransformation enzymes, pointing at an increased toxification or decreased detoxification, in women with a history of pre-eclampsia, as compared to healthy controls (p < 0.001).

CONCLUSION

Women withthe simultaneous occurrence of two or more genetic polymorphisms in the above-mentioned biotransformation enzymes, most probably resulting in a disturbed detoxification capacity, may be at increased risk for pre-eclampsia.

Glutathione S-transferase phenotypes in relation to genetic variation and fruit and vegetable consumption in an endoscopy-based population

High glutathione S-transferase (GST) activity may contribute to colorectal cancer prevention. Functional polymorphisms are known in the GSTM1, GSTT1, GSTA1 and GSTP1 genes. The influence of these GST polymorphisms and recent fruit and vegetable consumption on GST levels and activity has not been investigated simultaneously in a human population. Also, it is not clear if blood GST activity reflects rectal GST activity. Therefore, we determined GST polymorphisms in 94 patients scheduled for sigmoidoscopy. Rectal GST isoenzyme levels (GSTM1, GSTM2, GSTT1, GSTA and GSTP1) were measured by quantitative western blotting, and rectal and white blood cell total GST activities were measured spectrophotometrically using 1-chloro-2,4-dinitrobenzene (CDNB) as a substrate. Vegetable and fruit consumption was assessed by dietary record. As expected, the GSTM1 and GSTT1 deletion polymorphisms, and the GSTA1 g.-69C-->T polymorphism significantly affected the respective isoenzyme levels. Also, rectal GST isoenzyme levels differed between those with and without recent consumption of Alliaceae, Cucurbitaceae, Apiaceae and citrus fruit. Rectal GST activity, however, was not clearly influenced by fruit and vegetable consumption. It was most significantly determined by the GSTP1 c.313A-->G polymorphism; compared with the 313AA genotypes, the 313AG and 313GG genotypes showed 36 and 67 nmol/min/mg protein (P < 0.001) lower GST activity, respectively. The correlation between rectal and white blood cell GST activities was low (r = 0.40, P < 0.001), and the relevance of the various genetic and dietary factors appeared to differ between the two tissues. In conclusion, this study indicates that the GST enzyme system is influenced by both GST polymorphisms and consumption of fruits and vegetables. The latter appeared more important for individual rectal GST isoenzyme levels than for total GST activity, which could affect detoxification of isoenzyme-specific substrates. The study results do no support the use of white blood cell GST activity as a surrogate measure for rectal GST activity.

Decreased levels of mucosal detoxification enzymes in the pouch of patients with familial adenomatous polyposis

BACKGROUND

Adenomas can develop in the pouch after colectomy with ileal pouch-anal anastomosis (IPAA) in patients with familial adenomatous polyposis (FAP). Glutathione S-transferases (GSTs) have a protective role in carcinogenesis. GST activity is much higher in the ileum than in the colon. The present study examined the hypothesis that the protective capacity of GSTs may be lowered as a result of colonic metaplasia of the ileal pouch.

METHODS

Levels of GSTs, glutathione and cysteine, and the degree of inflammation and colonic metaplasia were quantified in biopsies from the pouch and afferent loop of 26 patients with FAP.

RESULTS

GST enzyme activity, and levels of GST alpha, glutathione and cysteine in the pouch were significantly lower than those in the afferent loop (308 versus 398 nmol per min per mg protein (P<0.001), 4604 versus 5286 ng per mg protein (P=0.010), 27.1 versus 34.8 nmol per mg protein (P=0.023) and 0 versus 4.8 nmol per mg protein (P=0.009) respectively). No correlation was found between inflammation or colonic metaplasia of the pouch and GST enzyme activity in the pouch.

CONCLUSION

After IPAA, GST detoxification activity in the pouch is significantly lower than that in the afferent ileal loop, which may promote tumorigenesis.

Assessment of oxidative stress in chronic pancreatitis patients

AIM: To assess the levels of antioxidant capacity and oxidative damage in blood of chronic pancreatitis (CP) patients in comparison with those in healthy control subjects, by using several different analytical techniques.

METHODS: Thirty-five CP patients and 35 healthy control subjects were investigated prospectively with respect to plasma levels of thiols, ferric reducing ability of plasma (FRAP, i.e. antioxidant capacity), levels of protein carbonyls and thiobarbituric acid reactive substances (TBARS). Additionally, we evaluated the production of reactive oxygen species (ROS) in whole blood.

RESULTS: The antioxidative thiols including cysteine, cysteinylglycine and glutathione were significantly lower in CP patients. In addition, the non-enzymatic antioxidant capacity was significantly lower in CP patients, which correlated with the amount of oxidative protein (protein carbonyls) and the extent of lipid damage (TBARS), both were significantly higher in CP patients. The ROS production in whole blood after stimulation with phorbol 12-myritate 13-acetaat, demonstrated a strong tendency to produce more ROS in CP patients.

CONCLUSION: Oxidative stress may contribute to the pathogenesis of chronic pancreatitis by decreasing antioxidant capacity and increasing oxidative damage in CP patients may be a rationale for intervention with antioxidant therapy.

No evidence for oxidative stress in patients on home parenteral nutrition

BACKGROUND & AIMS

Patients on total parenteral nutrition depend on the composition of the nutritional formulation for maintenance of their oxidant-antioxidant balance. The present observational study was conducted to evaluate a substantial part of our patient population for evidence of oxidative stress.

METHODS

Venous blood samples were obtained from 41 patients on home parenteral nutrition (HPN) and 41 healthy controls. Glutathione in plasma and whole blood, glutathione peroxidase and superoxide dismutase in erythrocytes and total plasma antioxidant capacity were measured to assess the antioxidant status. Oxidant status was evaluated by measuring the production of reactive oxygen species by leukocytes. Oxidative damage was assessed by measuring lipid peroxidation and protein oxidation products.

RESULTS

Patients on HPN showed some signs of increased oxidative stress, however, there were no signs for oxidative damage, compared with healthy controls. In addition, activity of any underlying disease was not associated with increased oxidative stress.

CONCLUSIONS

The current treatment regime for patients on HPN at our center apparently prevents the development of significant oxidative damage, despite signs of some oxidative stress. Based on these data, adaptations in the composition of parenteral nutritional formulations do not seem mandatory.

Expression of the glutathione enzyme system of human colon mucosa by localisation, gender and age

BACKGROUND

The glutathione S-transferases (GST) can metabolise endogenous and exogenous toxins and carcinogens by catalysing the conjugation of diverse electrophiles with reduced glutathione (GSH). Variations of GST enzyme activity could influence the susceptibility of developing cancers in certain areas of the gastrointestinal tract.

AIMS

The expression of the components of the glutathione system in the colon was investigated with respect to age, gender and localisation.

METHODS

Biopsies of macroscopically normal mucosa from both proximal and distal colon were collected from 208 patients (106 females, 102 males; mean age 61 years), who underwent colonoscopy for various clinical reasons. GSH content, total GST enzyme activity and the levels of the GST isoenzymes glutathione S-transferase P1 (GSTP1) and glutathione S-transferase M1 (GSTM1) were determined.

RESULTS

GST enzyme activity, GSH and GSTP1 levels decreased significantly from proximal to distal colon (GST activity: 264 vs. 244 nmol/min/mg protein, p < 0.001, GSH content: 32 vs. 30 nmol/mg protein, p = 0.022 and GSTP1 levels: 2.25 vs. 2.10 mug/mg protein, p < 0.001). In female patients there was a significant stepwise increase of GST-activities and GSTP1 levels from the age of under 50 years to over 70 years. Oral sex hormone substitution among female patients between 50 and 70 years suppressed GST-activities and GSTP1 content.

CONCLUSIONS

The GSH-system in the colonic mucosa is expressed at a lower level in the distal colon (sigma) than in the colon transversum; whether this small difference translates into variations of incidence of colorectal cancer remains to be seen. Females express higher enzyme levels as they grow older, while in males no significant age effects were found. Elderly females might be better equipped with protective GSH-enzymes in the colon than males and this could contribute to the lower incidence of colorectal carcinomas in females.

Deficient UDP-glucuronosyltransferase detoxification enzyme activity in the small intestinal mucosa of patients with coeliac disease

BACKGROUND

Small intestinal malignancies in humans are rare; however, patients with coeliac disease have a relatively high risk for such tumours. Intestinal UDP-glucuronosyltransferases are phase II drug metabolism enzymes also involved in the detoxification of ingested toxins and carcinogens. As many toxins and carcinogens are ingested via food, the human gastrointestinal tract not only has an important role in the uptake of essential nutrients, but also acts as a first barrier against such harmful constituents of the food. Therefore, the gastrointestinal mucosa contains high levels of detoxification enzymes such as cytochromes-P450, glutathione S-transferases and UDP-glucuronosyltransferases.

AIM

To compare the UDP-glucuronosyltransferase detoxification capacity in small intestinal mucosa of patients with coeliac disease vs. that in normal controls.

METHODS

We assessed UDP-glucuronosyltransferase enzyme activities towards 4-methylumbelliferone in small intestinal biopsies of patients with coeliac disease (n = 22) and age- and sex-matched controls (n = 27).

RESULTS

Small intestinal UDP-glucuronosyltransferase enzyme activity in controls was significantly higher than in patients with coeliac disease: 0.55 +/- 0.27 vs. 0.35 +/- 0.16 nmol/min mg protein, respectively (mean +/- s.d., P = 0.005).

DISCUSSION

The low small intestinal UDP-glucuronosyltransferase detoxification activity in patients with coeliac disease may result in a deficient detoxification of potential carcinogens, and thus could explain in part the relatively high small intestinal cancer risk in these patients.

Role of epoxide hydrolase, NAD(P)H:quinone oxidoreductase, cytochrome P450 2E1 or alcohol dehydrogenase genotypes in susceptibility to colorectal cancer

Colorectal cancer (CRC) is one of the most common forms of cancer in Western countries. CRC has been associated with genetic and lifestyle factors. Individual susceptibility to CRC may be due partly to variations in detoxification capacity in the gastrointestinal tract. Genetic polymorphisms in detoxification enzymes may result in variations in detoxification activities, which subsequently might influence the levels of toxic/carcinogenic compounds, and this may influence the risk for CRC. Therefore, we determined whether polymorphisms in the genes coding for microsomal epoxide hydrolase (EPHX1), NAD(P)H:quinone oxidoreductase (NQO1), cytochrome P450 2E1 (CYP2E1) and alcohol dehydrogenase (ADH3) predispose to the development of CRC. DNA samples were obtained from 371 patients with sporadic CRC and 415 healthy controls. Patients and controls were all of Caucasian origin. All genetic polymorphisms were determined by polymerase chain reaction, eventually followed by restriction-fragment-length-polymorphism analyses, except for the EPHX1 codon 113 polymorphism, which was genotyped by an allele-specific discrimination assay. Calculation of crude Odds Ratios (ORs) revealed an increased risk for CRC associated with variant NQO1 (OR 1.5, 95% CI 1.1-2.0) and CYP2E1 intron 6 genotypes (OR 2.2, 95% CI 1.3-3.8). However, after adjustment for age and gender, logistic regression analyses only showed a statistically significant risk for CRC associated with variant NQO1 genotypes (OR 1.6, 95% CI 1.03-2.4). No associations were found between CRC and the other polymorphic genes as mentioned above. In conclusion, these data suggest that the presence of variant NQO1 genotypes, with expected reduced enzyme activities might enhance susceptibility to CRC.

High oxygen radical production in patients with sporadic colorectal cancer

It is hypothesized that excessive generation of reactive oxygen species (ROS) by phagocytes or leakage from mitochondria may harm key genes or proteins responsible for intestinal cell homeostasis. This may initiate the multistage process of colon cancer development. The present study investigates whether ROS production by whole blood may contribute to the etiology of colorectal cancer (CRC). Whole-blood oxygen radical production was measured by luminol-enhanced chemiluminescence and performed in fourfold with and without the stimuli phorbol 12-myristate 13-acetate (PMA) and serum-treated zymosan (STZ). We evaluated patients (i) with a history of sporadic CRC at least 3 months after surgery, (ii) who were hereditary nonpolyposis colorectal cancer (HNPCC) gene carriers, and (iii) with familial adenomatous polyposis (FAP). For each patient group (n = 20) an age- and gender-matched healthy control group was measured. Unstimulated and PMA-stimulated values for maximal oxygen radical production were significantly higher in patients with sporadic CRC in comparison to controls (p = 0.01, p = 0.04, respectively). Furthermore, trends toward higher unstimulated and PMA-stimulated area under the curve chemiluminescence were seen in CRC patients compared with controls (p = 0.08, p = 0.09, respectively). In patients with HNPCC or FAP, unstimulated or PMA- or STZ-stimulated chemiluminescence did not differ compared to their control groups. In conclusion, whole-blood oxygen radical production was higher in patients with a history of sporadic CRC, in comparison with age- and gender-matched controls, which indicates that ROS may play a role in the etiology of sporadic CRC.

Detoxification enzymes in the duodenal mucosa of patients with familial adenomatous polyposis

Unlikely to be involved in duodenal polyposis

No association between genetic polymorphisms in NAD(P)H oxidase p22phox and paraoxonase 1 and colorectal cancer risk

BACKGROUND

Impaired metabolism of ingested toxic or carcinogenic compounds is a postulated mechanism underlying colorectal cancer (CRC). Furthermore, it is suggested that reactive oxygen species (ROS) may play a role in human cancer development. Polymorphic variations in NAD(P)H oxidase p22phox and paraoxonase 1 (PON1) enzyme activities may alter superoxide production or the rate of chemical metabolism, respectively, and this may influence the risk for CRC. Therefore, this study was designed to determine whether the distribution of polymorphisms in NAD(P)H oxidase p22phox and PON1 genes was different in sporadic CRCpatients versus healthy controls.

MATERIALS AND METHODS

The study participants (365 cases and 354 controls) were all of Caucasian origin. NAD(P)H oxidase p22phox H72Y, and PON1 L55M and Q192R polymorphisms were genotyped by polymerase chain reaction, eventually followed by restriction-fragment-length-polymorphism analyses.

RESULTS

Comparison of CRC patients and controls revealed no significant differences in genotype distributions or allele frequencies for polymorphisms in the NAD(P)H oxidase p22phox and PON1 genes. Investigation of potential associations between the variant NAD(P)H oxidase p22phox or PON1 alleles and the clinical characteristics, tumour location or tumour stage, also did not reveal statistically significant associations.

CONCLUSION

Variant genotypes of NAD(P)H oxidase p22phox and PON1 do not contribute to the susceptibility to CRC.

Genetic polymorphisms in UDP-glucuronosyltransferases and glutathione S-transferases and colorectal cancer risk

Colorectal cancer (CRC) is one of the most common malignancies in the Western world showing an increasing incidence, and has been associated with genetic and lifestyle factors. Individual susceptibility to CRC may be due partly to variations in detoxification capacity in the gastrointestinal tract. Genetic polymorphisms in detoxification enzymes may result in variations in detoxification activities, which subsequently might influence the levels of toxic/carcinogenic compounds, and this may influence the risk for CRC. To determine whether genetic polymorphisms in detoxification enzymes predispose to the development of CRC, 371 patients with sporadic CRC and 415 healthy controls were genotyped for polymorphisms in the important detoxification enzymes UDP-glucuronosyltransferase UGT1A1, UGT1A6, UGT1A7 and UGT1A8, and glutathione S-transferase GSTA1, GSTM1, GSTP1 and GSTT1. Patients and controls were all of Caucasian origin. DNA was isolated from either blood or tissue and tested by polymerase chain reaction followed by restriction fragment length polymorphism analyses. Logistic regression analyses showed significant age- and gender-adjusted risks for CRC associated with variant genotypes of UGT1A6 [OR 1.5, 95% (confidence interval) CI 1.03-2.3] and UGT1A7 (OR 2.4, 95% CI 1.3-4.6), whereas no associations were found between CRC and the other polymorphic genes as mentioned above. In conclusion, the data suggest that the presence of variant UGT1A6 and UGT1A7 genotypes with expected reduced enzyme activities, might enhance susceptibility to CRC.

Genetic polymorphisms in alcohol-metabolizing enzymes and chronic pancreatitis

AIMS

Alcohol misuse is now regarded as an important risk factor for development of chronic pancreatitis (CP). However, not every alcohol misuser develops CP and it therefore might be suggested that susceptibility could be further influenced by inter-individual variations in the activities of alcohol-metabolizing enzymes. Several genetic polymorphisms that may affect the activities of alcohol-metabolizing enzymes have been described. Therefore we determined whether polymorphisms in the genes for alcohol dehydrogenase 3 (ADH3) or cytochrome p450 2E1 (CYP2E1) predispose to the development of CP.

METHODS

DNA samples were obtained from 142 adult CP patients with hereditary (n = 21), alcoholic (n = 82) or idiopathic (n = 39) CP. DNA from 128 healthy controls and from 93 alcoholic controls was analysed for comparison. Patients and controls were all of Caucasian origin. Genetic polymorphisms in ADH3 and CYP2E1 were determined by PCR, followed by restriction-fragment-length-polymorphism analyses in all subjects.

RESULTS

The frequencies of ADH3 and CYP2E1 c1c2 genotypes did not differ between CP patients and alcoholic and healthy controls. However, a trend for a higher frequency of the CYP2E1 intron 6 D allele was demonstrated in patients with alcohol-induced CP, compared to that of healthy controls (OR = 3.03, 95%CI = 1.0-9.1) or alcoholic controls (OR = 2.76, 95%CI = 0.9-8.7).

CONCLUSIONS

These data suggest that the presence of the CYP2E1 intron 6 DD genotype might confer a higher risk of alcoholic CP.

Effects of dietary anticarcinogens and nonsteroidal anti-inflammatory drugs on rat gastrointestinal UDP-glucuronosyltransferases

BACKGROUND

Dietary compounds or nonsteroidal anti-inflammatory drugs (NSAIDs) may reduce cancer rates. Elevation of phase II detoxification enzymes might be one of the mechanisms leading to cancer prevention. We investigated the effects of dietary anticarcinogens and NSAIDs on rat gastrointestinal UDP-glucuronosyltransferases (UGT).

MATERIALS AND METHODS

Diets of Wistar rats were supplemented with oltipraz, alpha-tocopherol, beta-carotene, phenethylisothiocyanate (PEITC), sulforaphane analogue compound-30, indole-3-carbinol, D-limonene, relafen, indomethacin, ibuprofen, piroxicam, acetyl salicylic acid or sulindac. Hepatic and intestinal UGT enzyme activities were quantified by using 4-nitrophenol and 4-methylumbelliferone as substrates.

RESULTS

Compound-30, D-limonene, indomethacin, ibuprofen or sulindac enhanced proximal small intestinal UGT activities. Only compound-30 was able to induce mid- and distal small intestinal UGT activities. Large intestinal UGT activities were increased by ibuprofen and sulindac, whereas oltipraz, PEITC and D-limonene gave enhanced hepatic UGT activities.

CONCLUSION

Mainly rat proximal small intestinal and hepatic UGT enzyme activities were induced by dietary anticarcinogens or NSAIDs. Enhanced UGT activities might lead to a more efficient detoxification of carcinogenic compounds and thus could contribute to the prevention of gastrointestinal cancer.

Induction of rat hepatic and intestinal UDP-glucuronosyltransferases by naturally occurring dietary anticarcinogens

Gastrointestinal tumours are among the most common malignancies in Western society, the majority of which are associated with dietary and lifestyle factors. Many dietary or lifestyle factors have been identified which may have toxic or carcinogenic properties. However, several dietary compounds also able to reduce gastrointestinal cancer rates in both humans and animals have been characterized. Though the exact mechanism leading to the anticarcinogenic action of these compounds is not fully known, it has been demonstrated that this chemopreventive capacity may be due to elevation of the glutathione S-transferase detoxification enzymes. Here we have investigated the effect of several anticarcinogens on the gastrointestinal UDP-glucuronosyltransferase (UGT) enzymes. Diets of male Wistar rats were supplemented with ellagic acid, ferulic acid, Brussels sprouts, quercetin, alpha-angelicalactone, tannic acid, coumarin, fumaric acid, curcumin and flavone, separately, and combinations of alpha-angelicalactone and flavone. Hepatic and intestinal (proximal, mid and distal small intestine and colon) UGT enzyme activities were quantified using 4-nitrophenol and 4-methylumbelliferone as substrates. All anticarcinogens tested increased UGT enzyme activity with both substrates, at one at least of the five different sites investigated. alpha-Angelicalactone, coumarin and curcumin showed enhanced UGT enzyme activities at all five sites. Both small and large intestinal UGT enzyme activities were increased by quercetin, alpha-angelicalactone, coumarin, curcumin and flavone. Except for tannic acid, all agents induced hepatic UGT enzyme activity. Furthermore, dietary administration of alpha-angelicalactone and flavone, given individually or in combination, enhanced the UGT detoxification system in the liver and, to a lesser extent, in intestine. In conclusion, induction of gastrointestinal UGT enzyme activities after consumption of dietary anticarcinogens may contribute to a better detoxification of potentially carcinogenic compounds and subsequently to the prevention of gastrointestinal cancer.

Glutathione S-transferase Mu null genotype affords protection against alcohol induced chronic pancreatitis

Glutathione S-transferases (GSTs) play critical roles in providing protection against electrophiles and products of oxidative stress, by catalysing the formation of glutathione conjugates and by eliminating peroxides. Most extensively studied are four main families of human cytosolic GST: GSTAlpha(A), GSTMu(M), GSTPi(P) and GSTTheta(T). Absence of GSTM1 or GSTT1 can be attributed to absence of the GSTM1 or GSTT1 gene products (null genotype) in approximately 50% and 20% of the Caucasian population, respectively. We investigated whether polymorphisms in the GSTM1, GSTT1 and GSTP1 genes modified the risk for chronic pancreatitis (CP). DNA samples were obtained from 142 adult CP patients with alcoholic (n = 79), hereditary (n = 21) or idiopathic (n = 42) origin. DNA from 204 healthy controls and from 57 alcoholic controls was analysed for comparison. Patients and controls were all of Caucasian origin. Genetic polymorphisms in GSTs were determined by PCR, eventually followed by restriction-fragment-length-polymorphism analyses in all subjects. The rates of GSTT1 and GSTP1 genotypes did not differ between CP patients and healthy controls. However, GSTM1 null genotypes were significantly less common in alcoholic CP patients (OR = 0.56, 95% CI: 0.33-0.95) as compared to healthy controls and to alcoholic controls (OR = 0.52, 95% CI: 0.26-1.04). Age- and sex-adjustment bolstered our finding (adjusted OR = 0.48, 95% CI: 0.26-0.89). The frequency of the GSTM1 null genotype is significantly lower in alcoholic CP patients, especially young female. This suggests that GSTM1 null alcohol users, particularly young female, are less susceptible to CP.

Genetic polymorphisms in biotransformation enzymes in Crohn's disease: association with microsomal epoxide hydrolase

BACKGROUND

Mucosal biotransformation enzymes can modify toxic compounds in the gut. As chemical or oxidative stress may be involved in the aetiology of Crohn's disease, genes encoding for enzymes involved in the prevention of such stress may be candidates for genetic susceptibility to Crohn's disease.

AIM

To assess the association of Crohn's disease with genetic polymorphisms in cytochrome P450 1A1, glutathione S-transferases mu-1, pi-1, and theta-1, and epoxide hydrolase.

METHODS

chi(2) square analysis was used to compare frequencies of polymorphisms between 151 patients with Crohn's disease and 149 healthy controls.

RESULTS

In patients, a genetic polymorphism in exon 3 of the microsomal epoxide hydrolase gene was distributed significantly different compared with controls (chi(2)=23.7; p<0.0001). All other polymorphisms tested were equally distributed between patients and controls.

CONCLUSIONS

Microsomal epoxide hydrolase may play a role in the pathophysiology of Crohn's disease. Furthermore, the epoxide hydrolase gene is located on chromosome 1q, close to a region previously linked to Crohn's disease.

Glutathione and glutathione S-transferases A1-1 and P1-1 in seminal plasma may play a role in protecting against oxidative damage to spermatozoa

OBJECTIVE

To study the levels of glutathione, glutathione S-transferase A1-1, and glutathione S-transferase P1-1 in seminal fluid of fertile and subfertile men.

DESIGN

Retrospective case-control study.

SETTING

Departments of gastroenterology, obstetrics and gynecology, and epidemiology and biostatistics in a university medical center.

PATIENT(S)

Twenty-five subfertile men visiting the fertility clinic and 25 fertile men from midwife practices were recruited.

INTERVENTION(S)

Collection of semen of subfertile and fertile men.

MAIN OUTCOME MEASURE(S)

Plasma levels of glutathione and glutathione S-transferases A1-1 and P1-1 in relation to seminal characteristics.

RESULT(S)

Glutathione, glutathione S-transferase A1-1, as well as glutathione S-transferase P1-1 were found in considerable amounts in seminal fluid of subfertile and fertile men. No differences between groups were found for glutathione S-transferases A1-1 and P1-1. Also, no associations with sperm count, motility, or morphology could be detected. Fertile men had significantly higher glutathione levels as compared with the case of subfertile men. Associations of glutathione with sperm motility quality (r(s) = 0.321) and abnormal sperm morphology (r(s) = -0.496) were found.

CONCLUSION(S)

The presence of glutathione S-transferases A1-1 and P1-1 in seminal fluid suggests a role in the protection against (oxidative) damage of spermatozoa, whereas glutathione may play a role in male fertility.